JPS5826638B2 - High frequency lighting fluorescent lamp dimmer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency lighting fluorescent lamp dimmer that enables preset dimming by using a constant power circuit for inputting a high-frequency variable power supply voltage.

In general, high-frequency lighting type residential fluorescent lamps are subject to restrictions such as the suppression of RFI and the use of preheating start-up type fluorescent lamps, and it is difficult to satisfy multiple functions such as rabbit starting characteristics and dimmability. Although necessary, it is very difficult to satisfy the above conditions.

On the other hand, in the case of high-frequency lighting of a large discharge lamp of several hundred W, for example, the performance and functions that must be met are simple in a sense.

By the way, preheat-starting type fluorescent lamps are premised on being driven by a so-called current source, which supplies current through a high impedance from the power supply, so rapid starting is performed by heating the cathode heating winding with the power supply voltage. If this is done, good compatibility between the fluorescent lamps used cannot be expected.

In addition, in so-called rapid starting circuits that are connected to commercial waves, it is common to make the magnetic circuit as small as possible by using a small cathode heating current and a small starting voltage. It is necessary to provide an auxiliary device, and furthermore, when a so-called electronic rapid starting circuit is used, there is a risk that lighting errors may occur depending on the kick voltage.

Furthermore, in order to perform dimming during high frequency lighting, it is out of the question to perform flow angle control in the same way as when lighting on commercial waves, in terms of RFI, that is, radio wave interference, and also to adjust the driving frequency by varying the drive frequency by variable impedance. When using light, the optimum operating point cannot be maintained, resulting in waveform distortion and a decrease in efficiency.Furthermore, when reducing the total light amount to 1/2 of the total light amount or 1/3 of the total light amount, the driving frequency may change. 2 to 3 times, it becomes difficult to balance ultra-audio frequency operation, suppression of radio wave interference, and Q.

Experiments have shown that controlling the light by varying the inductance by superimposing a bias direct current is out of the question in terms of radio wave interference due to nonlinear operation during lighting.

This invention combines the above-mentioned severe performance and diverse functions.
The object of the present invention is to provide a high-frequency lighting and high-light control device for residential use, for example, which can meet the above requirements.

Next, the present invention will be described in detail with reference to drawings showing embodiments thereof.

In Figure 1, E is a high-frequency power source that has a constant output frequency and can vary the output voltage, that is, a high-frequency variable voltage power source, and L is a preheat-start type fluorescent lamp whose power supply terminals are connected to the power source E. , 2□ is a first impedance element connected between both terminals of the fluorescent lamp on the opposite side from the power source E, and z2 is connected in series between one end of the power source E and one power source terminal of the fluorescent lamp. A second impedance element Z3 is a third impedance element provided between both source side terminals of the fluorescent lamp, and each impedance element Z1.
Z2. A constant voltage power circuit is formed by Z3.

The cathode heating current Ir necessary for dimming is given because the lamp voltage Et of the fluorescent lamp is almost constant during lighting.

Since the lamp current Id is proportional to the output voltage of the power source E, dimming is possible by variably setting the output voltage of the power source E.

At startup, the second impedance element Z2 and the first and third impedance elements
Impedance element z1. The constant power circuit of Z3 provides substantially constant power to the first impedance element z1, and the cathode preheating current Ipre and starting voltage Est of the fluorescent lamp are both substantially constant, making it possible to perform so-called precent dimming. .

Figure 2 shows a series circuit of a first coil L1 and a first capacitor C1 as a first impedance element z1 added to the circuit of Figure 1, and a series circuit of a first coil L1 and a first capacitor C1 as a second impedance element L2 in a common magnetic path with the first coil L1. The second coil L2,
Second capacitor C2 as third impedance element Z3
Figure 3 shows an equivalent circuit to the circuit in Figure 2, where Rt is the lamp current button and the equivalent lamp resistance Rf which gives the effective value of the lamp voltage is the filament resistance. , b and c are the first inductances
Letting the mutual inductance of the second coils L, , L2 be M, in the case of additive polarity, Ll +M - M, respectively.

L2+M, respectively L1-M for depolarization.

L2-M, +M.

When the fluorescent lamp is activated, that is, when it is turned on, due to the non-linearity of the voltage-current characteristics of the lamp L during high-frequency lighting as shown in FIG. For the equivalent lamp resistance R1 of the lamp L, the second coil L2 and the second
It is filtered by a low pass filter by capacitor C2.

In this case, the high frequency waves filtered by the filter are further attenuated by about 40 dB compared to a filter used in a normal light control device.

In this way, it can be said that it is a desirable property that the lighting circuit itself constitutes a strong filter.

Furthermore, as shown in FIG. 5, the second capacitor C2 in the side path acts effectively against the anode vibration and cathode vibration that generate so-called fluorescent lamp noise, suppressing the fluorescent lamp noise. .

Furthermore, in order to obtain good compatibility in rapid starding using a preheat-starting type fluorescent lamp, it is best to apply a sufficient cathode heating current under current source drive and a sufficient starting voltage. In Fig. 3, when the fluorescent lamp is turned on, the equivalent lamp resistance Rt=■, and the mutual reactance XM of the first coil L□ and the second coil L2 becomes much smaller than the reactance XC2 of the second capacitor C2. By setting the starting voltage (E
S t ), lamp voltage (E7), preheating current (Ipre
) = The following relationship occurs between the cathode residual current Ir during lighting, and since there is a degree of freedom in the output voltage of the power source E, E s t /E l or I p r e /
I r can take a value of, for example, 3 or 6, thus providing a sufficient preheating current 1 pre as well as a starting voltage Est.

Also, unlike electronic starters, this circuit has an order of magnitude more powerful starting voltage source and reliable starting, there is no problem with the starter restarting, and it is probably compatible with rapid start tubes of the same rating. It seems to me.

This circuit can be said to be in the best condition for ensuring compatibility, but the tradeoff for increasing compatibility is an increase in inverter capacity, and for this, starting operation must be changed. One possible method is to suppress the continuous capacity as much as possible by using a suitable protector that provides a short-time rating rather than a continuous rating.

Furthermore, by fixing the output frequency of power source E to a constant value and varying the output voltage of power source E, it is possible to perform dimming without causing waveform interference (radio wave interference) during high frequency lighting, and the output of power source E It goes without saying that the voltage and lamp current Id are in a proportional relationship, and it is desirable for securing the cathode heating current (usually a constant current is ensured by a heater transformer) necessary for dimming the hot cathode fluorescent lamp, and for practical purposes. Preset dimming, and thus self-start without cold start even when dimming, is possible with this circuit as follows.

In other words, it is possible to provide an almost constant residual current Ir during lighting because, as a characteristic of the discharge lamp, the lamp voltage does not change much even if the lamp current is changed significantly, and is kept fairly constant. The preheating current I
Since there is a high degree of freedom in selecting the prep residual current Ir and the starting voltage Est, they can be set to predetermined values.

It should be noted that it is rather preferable that the lamp voltage increases slightly when the lamp current is sensed because the residual current Ir increases somewhat, and since the preheating current Ipre and the starting voltage Est are roughly in a proportional relationship, Regarding polar wear, the preheating current Ipre and the starting voltage Est can be considered to have a complementary relationship, and the change in the preheating current Ipre with respect to the change in the power supply voltage E, and therefore the change in the starting voltage E, is kept almost constant, Good starting characteristics can be maintained.

The reason why the preheating current Ipre and the power supply voltage E are kept almost constant is that this circuit constitutes a kind of multi-resonant circuit, and at the point where the output voltage of the power supply E is high, the first capacitor c0 and the The preheating current I pre is generated by the saturation of the inductor in the phase advance circuit by the first coil L1.

Changes in the starting voltage E are suppressed, and in areas where the output voltage of the power source E is low, control is performed by boosting due to resonance between the non-saturated second coil L2 and the second capacitor C2.

In the case of additive polarity, the magnetomotive force at startup is large, for example, three times the magnetomotive force during lighting, so that saturable operation at startup and non-saturated operation during lighting can be used.

Figure 6 uses a ferrite core in the magnetic circuit, the mutual inductance is additive, a standard high-frequency power supply and a pseudo load, and shows the starting voltage Es ty, preheating current Iprey, lamp current Id, and cathode residual current Ir relative to the power supply voltage. It shows the characteristics.

On the other hand, when the lamp current It is increased, a double spot is formed, and this is based on the cathode residual (heating) current that is 90° in phase with respect to the lamp current. It is determined that it forms a high-output lighting circuit or a long-life circuit.

In addition, there is no need to use a leakage magnetic path in the magnetic circuit,
A structure with a normal coupling coefficient of approximately 1 is sufficient, and the circuit elements are one core, two coils, and two capacitors, and it can be said to be a simple structure if its functions are considered.

Incidentally, since resonance with the second capacitor C2 in the side path is at a non-saturation level, it is advantageous to have one that can easily maintain accuracy.

As described above, according to the high frequency lighting fluorescent lamp dimmer device of the present invention, in response to the high frequency variable power supply voltage input, the constant power circuit supplies constant power to the first impedance element at startup, and the fluorescent lamp receives an almost constant power. By providing a cathode preheating current and starting voltage of 100%, and providing a cathode heating current that is almost constant depending on the lamp voltage while the fluorescent lamp is on, it is possible to achieve good pre-cent dimming and to effectively suppress radio wave interference. It has various effects such as rapid starting, long life, and simplicity of a preheating start type fluorescent lamp.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of one embodiment of the high frequency lighting fluorescent lamp dimmer device of the present invention, FIG. 2 is a circuit diagram of a more detailed embodiment of the circuit of FIG. 1, and FIG. 3 is a circuit diagram of a more detailed embodiment of the circuit of FIG. Equivalent circuit diagram of the circuit, 4th
The figure is a voltage-current characteristic diagram of a general fluorescent lamp during high-frequency lighting.
Fig. 5 is a voltage-current characteristic diagram of a fluorescent lamp using the circuit shown in Fig. 2, and Fig. 6 shows the voltage-current characteristics when a ferrite core is used in the magnetic circuit, the mutual inductance is additive, and a standard high-frequency power supply and a pseudo load are used. The figure shows a characteristic diagram for power supply voltage. ■...Easy frequency variable voltage power supply, L...Fluorescent lamp, Zipz2. Z3... 1st. 3rd impeder 7 elements, Ll, L2 --- 1st. 2nd coil, C,, C2... 1st coil. Second capacitor.

Claims (1)

[Claims] 1. A variable output voltage high frequency power source having a constant output frequency, a fluorescent lamp whose power supply side terminals are respectively connected to the power source, and a first impedance provided at both ends of the fluorescent lamp on the opposite side of the power source. a second impedance element provided between one end of the power source and one power source terminal of the fluorescent lamp; and a third impedance element provided between both source side terminals of the fluorescent lamp. and each of the impedance elements supplies a constant power to the first impedance element when starting the fluorescent lamp to provide a substantially constant cathode heating current and starting voltage to the fluorescent lamp, and 1. A high-frequency lighting fluorescent lamp dimmer comprising: a constant power circuit that applies a substantially constant cathode heating current to the fluorescent lamp according to the lamp voltage of the fluorescent lamp during lighting of the fluorescent lamp.